1. Field of the Invention
The present invention relates to a method for producing an optical fiber cord and an optical fiber tape cord, particularly to a method for producing a small-bore optical fiber cord and optical fiber tape cord useful for the manufacture of a highly dense, optics-related apparatus and its components.
2. Prior Art
Conventionally, an optical fiber cord is obtained by applying a resin coat over an optical fiber element line to turn it into an optical fiber core line, and then applying around the periphery of the optical fiber core line a PVC coat with resilient fibers such as aramid fiber, glass fiber, copper wire, PBO fiber, etc., intervened in between.
The optical fiber cord having the constitution as described above is produced as follows.
Firstly, a nylon tube (a) having a bore of a desired size is prepared as shown in FIG. 3(A), and resilient fibers (b) as described above are arranged longitudinally around the periphery of the nylon tube (a). Next, the nylon tube (a) having the resilient fibers (b) arranged around its periphery is inserted into a tubular PVC cover (c) as shown in FIG. 3(B). Then, an optical fiber element line (d) is inserted into the nylon tube (a) to produce thereby an optical fiber core line (e) as shown in FIG. 3(C), and the whole assembly is made an optical fiber cord A.
However, with the conventional method, all procedures necessary for the production of an optical fiber cord are practiced manually. Therefore, while it is comparatively easy to produce an optical fiber cord having a large bore size, production of a small bore fiber cord requires extra labor and time for completion because then it is often difficult to pass a nylon tube with resilient fibers arranged longitudinally around its periphery smoothly through a tubular PVC cover having a comparatively small size Accordingly, development of a method whereby it is possible to efficiently produce a small-bore optical fiber cord or small-bore optical fiber cord tape is urgently demanded, because nowadays optics-related apparatuses and their components are increasingly more compacted and densely packed.
This invention was derived from an attempt to meet such a demand arisen with respect to the problem inherent to the conventional method, and aims at providing a method for producing an optical fiber cord or an optical fiber cord tape which consists of preparing a dummy cord incorporating a replaceable line and resilient fibers, connecting the replaceable line of the dummy cord with an optical fiber core line, and replacing the replaceable line with the optical fiber core line, thereby making it possible to efficiently produce an optical fiber cord and optical fiber tape cord whether their bore is large or small, without degrading the quality of the cord product whatsoever.
The method according to this invention for producing an optical fiber cord and an optical fiber cord tape comprises preparing a dummy cord by placing a replaceable line at the center, arranging resilient fibers around the periphery of the replaceable line, and covering the assembly with a jacket; exposing both ends of the replaceable line and of resilient fibers from the jacket of the dummy cord; connecting one end of the replaceable line with an optical fiber core line or a unit core line of an optical fiber cord tape; and replacing the replaceable line with the optical core line or the unit core line.